Electric heating unit



Feb. 7', 1950 L. s. wElMl-:R

ELECTRIC HEATING UNIT Filed Jan. 19, 1946 Patented Feb. 7, 195() UNITED STATES PATENT vOFFICE ELECTRIC HEATING UNIT Application January 19, 1946, Serial No. .642,311

4 Claims'.` (Cl. 219-37) This invention relates to electric heating units, and particularly to insulating elements for supporting the resistance wire and which may be substituted for the original elements when broken.

The invention applies to heating units which are employed in ovens and the like having a plurality of coils of resistance wires or loops thereof disposed in parallel relation on a supporting member. The supporting member has a plurality of U-shaped members, in the nature of hangers, secured thereto in spaced but aligned relation. The projecting arms of the members are provided with apertures for receiving and supporting the ends of the insulating elements. The apertures comprise slots extending from the ends of the arms to communicate with circular holes disposed inwardly from the ends thereof. The insulating elements have truncated circular end portions in the nature of trunnions which pass through the slots in the ends of the arms in one position and when rotated 90 extend crosswse of the circular holes to thereby lock the elements in secured position.

One or more circular apertures extend through the insulating elements, one for each of the coiled resistance wires of the heating unit through which the coiled wires are threaded when initially assembled. Should an insulating element become broken, this may be replaced by another unit having slots communicating with the circular apertures from one edge of the element. The slots are preferably disposed at an angle to the axes of the apertures so that after the coiled wire has been passed through the slot into the aperture, the change of its position from the axis of the slot to that of the aperture will dispose the coil beneath overhanging portions of the slot and the coiled wire will be anchored within the aperture.

Accordingly, the main objects of the invention are: to secure insulating elements on hangers for supporting coiled resistance wires of a heating element which are replaceable by other units when broken; to provide U-shaped members having in the arms thereof cylindrical apertures communicating with slots which extend to the end of the arms'for receiving truncated circular portions on the ends of insulating elements which pass therethrough in one position and which are locked in position when rotated 90; to provide a plurality of insulating elements with apertures for receiving and supporting coiled resistance wires of a heater, which are joined by slots extending from one edge of the elements through which the coiled Wires may be inserted when disi- 2 posed in said apertures; and, in general, to provide an electric heating unit which is simple in construction, positive in operation and economical of manufacture.

Other objects and features of novelty of the invention will be specifically pointed out or will become apparent when referring, for a better understanding of the invention, to the following description taken in conjunction with the accompanying drawing, wherein:

Figure 1 s a plan view of a heating unit having insulating elements for supporting the coiled resistance wires embodying features of this invention;

Fig. 2 is an enlarged sectional view of the structure illustrated in Fig. 1, taken on the line 2-2 thereof;

Fig. 3 is a sectional view of the structure illustrated in Fig. 2, taken on the line 3-3 thereof;

Fig. 4 is a sectional view of the structure illustrated in Fig. 2, taken on the line 4--4 thereof;

Fig. 5 is a view of structure, similar to that illustrated in Fig. 2, showing a modified form thereof; and

Fig. 6 is a sectional view of the structure illustrated in Fig. 5, taken on the line 6 6 thereof.

Referring to the gures, a heating unit I, which is herein illustrated as being constructed for an oven, embodies a plate 2 made of metal having a central flanged opening 3, an end flange 4, and an opening 5 in which the insulating portion of a connecting plug 6 is secured, herein illustrated as by bolts 1. Terminals 8, 9 and IIJ are provided on the plug to which coiled resistance wires II and I2 are secured in the conventional manner. The resistance wire II forms an inner loop about the central opening 3, while the resistance wires I2 form a parallel loop outwardly thereof. The

inner loop is connected across the terminals 8 and 9 while the outer loop is connected across the terminals 9 and I0.

For supporting the resistance wires, a plurality of U-shaped supporting members I 3 are employed having the web portions Hl welded or otherwise secured to the plate 2. The arms I 5 of the U-shaped elements I3 extend outwardly from the plate 2 and are provided with cylindrical apertures I64 and slots I1 of less width than the diameter of the apertures forming a passageway from the end of the arm to the apertures I 6. insulating elements I8 for supporting the coiled wire are of rectangular construction having a length to fit between the arms I5 and having truncated cylindrical trunnion portions I9 e'xtending from each end. The width of the trun- 3 nion portions is such as to pass through the slot II, while the diameter of the cylindrical portion is substantially equal to the diameter of the apertures I6. After the element has been inserted between the arms I5 by passing the narrow width of the trunnion portions I9 through the slots I1, it is rotated 90 to have the trunnion portions of greatest .length extend across" the diameter of the apertures `:I6-to besecurely anchored to the arms I5.

A plurality of apertures are provided..

through the insulating elements I8.. through. which the coiled resistance Wires II and I2 are threaded and are held in position onthe plate vv2, as clearly illustrated in Figs I.: Slots 2l may bef provided through one wall of the insulating ele; A ments I8 communicating withl the apertures 20.

so that the coiled Wires may be passed into the apertures 20 through the slots 2l when originally.

assembled or after onefof the elements I8 has A brokenV andcanothenelement a HL.` having the slot 2i, is'.tsu'bstituteditherefor;r The; element ifvvhic'h isdamagediina-y be'broken up-t'in smail sections through each of the apertures 20 .so'that the parts may be removed; Vwithout damaging thecoiled resistancefwiresl I and: I'2.-` Thereafter ,aninsulat` element I il,- havingf the v slotsf2 I ftherein, may

havethe trunnion-.portions I9 z passed into the apertures: I 6 through the slots ;I'I,` and after the wires have been aligned :.Withtheev slotsl 2l the element-,- lvisfrotatedy through.' 90 to lock-the trunniomportions-IS withinthesarms I5 and to havef-the'resistance vWires I I and l2 disposed` in the slots 2|. The resistance wires may then be pushedfthroughi the :slots-2l into. the .apertures 20 Wherethey'fare anchored inf position, as illustrated in Figs. 2 and 5.

In'lii-ggz.- the .slots-s2 I- are-disposed atzan angle tofthefaxesoifthe aperturesfZ butoithe: same diameterfsoL thatthe resistancewires II and* -I2 will readily `pass-through .-the.slots,2.l into the apertures 1.2.0,. Whenthe-` axes. -o the. coiledresistanceWirescOincide-with the axes of' theapertures 20, the wires are locked in position by the overhanging-vendso the wall. of. the slotsgZI which are` disposed atan angletotheiaxesot the coiled wires.

In. Fig., 5, slots4 224 are similar` .to slotsV 2 I with the-exception that they are Aof slightly less diam,- eter` than-.the diameter of. the`4V apertures v20 but aredisposed parallel tothe-axes .of the apertures. The coiled resistancawires Il and. I2are reduced in -diarneter by the ychangefotlle pitchoi Athe coils `when. passing through- .slots ,andwhen. re-v turned. .to-.theorignal pitch; thecoils ,Willbe se. curely anchored: within, .the apertures ,20L

WhentheelementsI are provided with apertures 20`without theslots 2l and 22, the resistance wires H. andIZ are fed thereon, before Athe elementsareattachedto the U.-shaped elementsIS. It is within the purview of the invention to vapply thecoiled. Wires .to the plate ,2.and, assemble the insulatingg elements seriatimnon ythe.. supporting members. I3. when slots .arev provided inthe Yele ments, communicating with. the apertures. which receivethe. Wires.. Aiterany oneof the. units becomes damaged-,z it maybe broken. through. the apertures 2li-and. the `pieces removedso` that Va new.. insulating.. elementy may .be .applied to Y the heating unit, as pointed. out hereinabove..

What. is claimedis.:l

LA; heatingunitembodying. aplate and a coiled tresistarrce:l wire, .arms extending from `the platefcontainng anzaperture Joined by as... slot ,of

lessewidthithamtheewidth.:of .the aperture,v and.

insulating elements having trunnion portions at the ends, the truncated portions being so formed as to pass through the slots when in one position and when rotated from said position to be secured in the apertures, said insulating elements containing apertures and communicating slots, the Wall of the latter overhanging at least a portion'iofthe apertures irr which-the coil? resistance wires arefsecuredafter passing zthrough said slots.

2. A heating unit embodying a plate and a coiled resistance Wire, U-shaped brackets secured to ,theplate having spaced arms extending therefrom, each said arm containing a cylindrical apierturejoinedfbyfaslot of less Width than the diameter of theraperture, and insulating elements having:truncatedv cylindrical trunnion portions at the end,. the.width across the truncated portions being such as to pass through the slots and when rotated'90 to be secured in the apertures, said insulating elements containing apertures and communicating slotssin i-the former off. which the coiledresistancefyviresf are secured .after passing, through said,.slots;.saidy slotsin saidrinsulating elementsextending.atv amangle tothe axes-ofthe. :apertures for.. projecting. over the. coiled'l Yresistance. Wires. after passing.` therethroughvinto theapertures.v

3 .A vheating unit. embodying. aplate .and a coiled. resistance Wire,..UeshapedK brackets-securedtov the plate. having .spaced varms extendingthere-i from.` each..said armv containing. a.. cylindrical aperture joinedby a .slot of..less Widththan the diameter ofthe aperture, andinsulatingelements having.,truncated.. cylindrical. trunnion .portions at theendr the Widthacrossthe truncated portions being such. as topassthroughthe slots andW-hen rotated.A 90 to beesecuredin .theapertures, ,said insulatingv elements containing` apertures.V andr communicatingslotsin. the former .of which the coiled.' resistance .wires are. secured `after passing through .said slots.- .said .slots imsaidlinsulating elements' beinggof lesswidth thanthediameter ofthe apertures for securing the coiled resistance wires therein 4.' An insulating, element for a heating Vunit embodyingia supporting element 'havingrvspaced apertures provided. with communicating slots, said insulatingelement having an elongated body portion containingran aperture and a Ytrunnion at eachend, the width of the trunnions being greater.` than the thickness so'as to be capableof passing'through. the slot'into the communicating apertures in vrone positionv andto be retained in the apertures when rotated. ninety degreesfrom said position, said aperture in the bodyV portion bengjcapable of receiving and'supporting a .resistance/Wire; andan overhanging projection 'ade jacent ito-said'ilast aperture which' prevents the element from rotating onsits trunnions When'the resistance wire is retained thereby, Within the apertures.

LELAND'SL WEIMER'.

REFERENCES CITED The efollowingi; references. are for. recordgin: the le-ot. this v patent.;

UNITED STATESn PATENTS@ Pickup,--- Feb.l 9,1 1932 

